1. Field of the Invention
The present invention relates to a technique of displaying performance data, and more particularly to a performance information display apparatus and program.
2. Description of the Related Art
There has been a technique of causing an automatic performance apparatus to carry out automatic performance of a musical composition using performance data including plural pieces of note data indicative of pitch, sounding time period, etc. of musical tones constituting the musical composition. In general, an apparatus called an authoring tool is used to display and edit the contents of performance data used for the automatic performance apparatus.
FIG. 17 is a view showing how the contents of performance data are displayed by the authoring tool. The display format shown in FIG. 17 is generally referred to as piano-roll format in which a bar-shaped figure called a note bar indicates the contents of each piece of note data included in performance data. In the piano-roll format, the vertical direction as viewed in FIG. 17 corresponds to a pitch axis, and the horizontal direction corresponds to a time axis. For example, a note bar 1801 in FIG. 17 represents note data which indicates that a musical tone whose pitch is C3 is sounded from the 1.5th beat to the 3rd beat of the first bar. In the authoring tool capable of displaying note data in the piano-roll format, the user changes the position and length of a note bar by dragging a predetermined position thereof using a mouse pointer so as to change the contents of note data.
The above-mentioned piano-roll format is disclosed in e.g. Japanese Laid-Open Patent Publication (Kokai) No. 2002-49371.
By the way, the number of musical tones which can be sounded at the same time by the automatic performance apparatus is limited by processor capability, memory capacity, data bus data transfer capacity, etc. of the automatic performance apparatus (hereinafter referred to as “resources”) (hereinafter the upper limit of the number of musical tones will be referred to as “the maximum number of tones that can be sounded”). Upon reception of an instruction for sounding musical tones in number greater than the maximum number of musical tones that can be sounded, the automatic performance apparatus usually stops sounding only a musical tone of which sounding was started at the earliest among the musical tones of a musical composition being sounded, and allocates resources which have been used for sounding the musical tone to sounding of musical tones which are newly instructed to be sounded. The technique of sequentially allocating limited resources to sounding of different musical tones as above is called “DVA” (Dynamic Voice Allocation).
According to the DVA, it is possible to prevent the problem that a following musical tone is not sounded in the case where all the resources are used for sounding a preceding musical tone. However, if sounding of a preceding musical tone is forced to be stopped so as to sound a following musical tone, performance may become unnatural. For example, there may be a case where sounding of a musical tone in a melody part is stopped so as to sound a musical tone in an accompaniment part. To address this problem, the creator of performance data checks whether or not an instruction for sounding musical tones in number greater than the maximum number of musical tones that can be sounded is included in performance data, and e.g. erases less important musical tones as the need arises.
However, both ends of a note bar in the direction of the time axis, which is displayed in the piano-roll format by the authoring tool, indicate note-on timing and note-off timing of corresponding note data, and usually, the sounding time period of a musical tone indicated by the note bar does not correspond to the actual sounding time period of a musical tone sounded by the automatic performance apparatus for reasons stated below.
Taking an example where piano keys are operated, the note-on timing and the note-off timing correspond to timing in which a key is depressed and timing in which a finger is released from the depressed key, respectively. A musical tone sounded by a piano usually includes a reverberant part which is sounded even after a finger is released from the key (hereinafter referred to as “the release part”). This also applies to musical instruments other than a piano. Thus, many of automatic performance apparatuses are adapted to continue sounding the release part for a while even after the note-off timing. The duration of the release part differs according to tone color, pitch, tone intensity, and so forth.
For example, in FIG. 17, the note-off timing of note data corresponding to the note bar 1801 is the third beat of the first bar, but there is the possibility that a musical tone sounded by the automatic performance apparatus according to this note data is continuously sounded even after the third beat of the first bar.
As stated above, the time period between the note-on timing and the note-off timing displayed by the authoring tool does not correspond to the sounding time period of a musical tone which is actually sounded, and hence the creator of performance data has to repeatedly edit and reproduce the performance data so as to check whether or not sounding is to be interrupted against his/her intention. For example, in FIG. 17, there is no overlap between the time period indicated by the note bar 1801 and the time period indicated by a note bar 1802. However, there is the possibility that sounding of the release part of a musical tone sounded according to the note bar 1801 is stopped so as to sound a musical tone according to the note bar 1802, and the creator cannot recognize this without reproducing performance data. It should be noted that many authoring tools are capable of displaying performance data in a staff format, a list format, and so forth other than the piano-roll format, and the above described problem applies to any of these display formats.